Sunday, November 1, 2009

Nuclear Banshees

As soon as the atomic bomb got small enough to be carried by tactical jet fighters, the Navy adopted the McDonnell F2H Banshee for it, first the F2H-2 as the -2B and then the -3/4.

The F2H-2B was externally similar to the F2H-2, but had some local strengthening of the wings so that the aircraft could carry a 1650-lb Mk 7 or a 3230 lb Mk 8 nuclear bomb on a big pylon underneath the port stub wing. The flaps on that side had a small cutout for clearance of the store. An in-flight refueling probe installation was subsequently developed that could be installed in place of the upper right 20mm cannon.

The -7 was a very large weapon which required increasing the pressure in the main landing gear strut to provide even minimal ground clearance. This is my guess at the pylon shape and bomb location; note that the shock strut has not yet been extended to provide a modicum of ground clearance. (Read on for a description of this system on the F2H-3/4, which may also have applied to the F2H-2B.) I've subsequently discovered (see below) that the tail cone had to be rotated clockwise (viewed from the rear) to provide clearance with the J34.

The F2H-2Bs were deployed only a few times, the first as a VC-4 detachment aboard Coral Sea to the Mediterranean beginning in April 1952. Other known detachments are VC-4 Det 7 aboard Franklin D. Roosevelt (CVB-42) and Det 44 aboard Lake Champlain (CVA-39) in 1953. Det 5 aboard Midway from December 1952 to May 1953 may have operated F2H-2Bs as well. There are also pictures of VF-82 F2H-2Bs aboard Champlain on its September 1954/April 1955 deployment and with VF-101 aboard Midway in 1955, shown here.

This is a picture of VC-4 F2H-2Bs aboard Lake Champlain sometime between June and November 1953. Note the flat-bottomed inboard stores pylon which was probably used for the Mk 8.

The F2H-2B was reportedly manufactured alongside the "stock" F2H-2 and -2Ps on the McDonnell production line. 27 were listed in an appendix to the F2H maintenance manual (Also see comment below).

For some reason, the location of both the refueling probe and the bomb mount were switched on the F2H-3/4, with the bomb now being carried on the right side and the refueling probe installed on the left side of the nose.

Whereas the F2H-2B had the cutout only in the left side flaps, the F2H-3/4 had the cutout in both flaps.

This is a preliminary sketch that I made once upon a time.

Thanks to the Gerald Balzer collection via Mark Nankivil, I now have better pictures of the Mk 7 and Mk 8 being carried by the F2H-3/4. (The Mk 7 shown has different fins that shown above and appears to be have a blunter nose.)

Note that all the shock struts are fully extended to provide a modicum of ground clearance. This also shows how the tail cone on the Mk 7 was rotated counterclockwise (looking forward), in order to clear the jet tailpipe.

Thanks to Larry Webster of the Quonset Air Museum, who provided a copy of the F2H-3/4 maintenance manual section on the main landing gear special strut extension, I can now accurately describe this feature. It was accomplished by adding two separate hydraulic fluid tanks. The fluid in both tanks was added to both shock struts to extend them fully for taxi and takeoff. (The nose gear strut extension was a separate system that was used on all F2H-3/4 catapult takeoffs.)

The struts were only partially deflated automatically when the landing gear was retracted "to permit a landing with stores still aboard" (presumably not on a carrier), which was why there were two separate tanks. To remove the remainder of the extra fluid from the struts for normal strut action, the pilot had to actuate a switch on the left console after he had lowered the landing gear.

This strut extension capability was provided by a kit, suggesting that it was only added to aircraft designated for the mission.
I have read that the F2H-2B strut extension was provided with "sleeves" added over the exposed piston. These reportedly dropped away after lift off. However, I don't have any documentation on that yet so I can't say that's myth or fact. It may have been an early kludge to provide the capability before the strut extension kit was developed. I also don't know whether just the bomb-side strut was extended on the F2H-2B or both sides. My guess would be both.

The Mk 8 picture was even more welcome. It was mounted on a slightly different pylon and also required the shock strut extension to provide clearance for the tail fin group. Note that this aircraft is equipped with the inflight refueling probe replacing one of the 20mm cannons and the fairing on the belly associated with this modification.

The shape shown below is the BOAR, a Mk 7 with a rocket attached for better separation from the instant sunshine it created.) Note again that the main landing gear shock strut is fully extended to provide what clearance there is but the nose strut has not yet been extended.

4 comments:

Thanks for posting Tommy, this stuff is gold! You should consider combining it all in a "Modeling Naval Jet Aircraft of the 50's 60's and 70's" book! Anyway, I enjoy your writing and it was good to hear your lecture at the Columbus Nats....

Tommy, great stuff!!! I noticed your reference to the early VC-4 Nuke Dets. For what it's worth, both of these Dets had F3D-2 Skyknights along as the Night Fighter complement. That's another aircraft that I admire, but there is so much bad info out there and everybody keeps repeating it. The first concerns the engine nacelles. They were NOT larger on the F3D-2 than on the F3D-1. Yes, the F3D-1’s nacelles were considerably larger than those on the three XF3Ds. One reason had to do with the F3D-1’s J-34-WE-34 engines being interchangeable vice the left-hand and right-hand arrangement of the J-34-WE-22’s in the XF3D; per your Naval Fights book. Additionally, at the time the F3D-1 was being developed for the Navy, the Air Force’s F-89 was having serious trouble and Douglas pressed the Air Force hard to adopt the F3D as their all-weather fighter too. The F3D-1 engine nacelles were further enlarged for increased airflow to accommodate either afterburning J-34-WE-15 or J-34-WE-17’s for the Air Force requirement. The F3D-1 was built in two series; the Series A which comprised the first 10 aircraft and the Series B which included the remainder of the production run. The difference being that the Series B airframes has the centerline speed brake (aka, AD-1 thru AD-4) eliminated. Also, if one references the F3D-1/F3D-2 Maintenance Manual with Illustrated Parts Breakdown, they will see the part numbers for the engine nacelles, air induction and exhaust components for both the F3D-1 and F3D-2 are one and the same.The second issue concerns the F3D-2B designation. The F3D-2B modification was actually a series of modifications incorporated in approximately 114 (if I remember correctly) of the standard F3D-2’s to allow them to carry either the MK-7 or MK-12 special weapons. I have a copy of the Douglas document that outlines the entire modification process. It was basically a two gun aircraft; removing two 20 MM weapons and armament components to allow for installation of the various ballistic and radar altimeter components required. The cockpit installations were all on the RO’s side of the aircraft. It also removed the tail warning radar and modified the right stores pylon to carry the weapons. The “pilot” aircraft for the modification was BuNo 127044, but I believe the intended plan was for the remainder of the aircraft to carry simply the F3D-2 designation (aka, nuclear capable F2H-3/4). I’m not sure how many of ‘the capable” aircraft were ever actually modified to this configuration. If one references the pilots handbook for the F3D-2, there are performance charts in the back for; a configuration of one 300 gal tank and one T-63 store (MK-7 shape) and a configuration of one 150 gal tank and one T-66 store (MK-12 shape) also.Most of this info was provided to me by the late, great Harry Gann when he was with Douglas in Long Beach, CA. He was a good friend and is missed greatly. Thanks and keep up the great work!!!

THE NUMBER OF F2H-2B NUCLEAR CAPABLE DASH-2 BANSHEEThorough investigation of the Aircraft History Cards, three additional F2H-2B were found;Bu.Nos. 124940 through 124942, together with 28 (not 25) F2H-2B listed above already, at least 31 F2H-2B were existed. Interesting to say, 124940 through 124942 were directly converted from F2H-2 to F2H-2B without via the interim designation of F2H-2BX (indicating the aircraft is under conversion), but other 28 were all converted from F2H-2 via F2H-2BX then to F2H-2B. All 31 F2H-2B were accepted by the Navy as straight fighter version F2H-2 and converted to F2H-2B after delivery.HIDEKI YAMAUCHI, AGC (Atsugi Gombey Club)

Thanks for providing a very interesting and knowledgeable comment. I don't know whether I just assumed that F2H-2Bs were built that way at the factory because of the BuNo sequence (usually in "pairs") or I read it somewhere. An oddity in that respect is that McAir's production numbers often do not parallel the BuNo, e.g. BuNo 125058 is Mac No. 383 and BuNo 125059 is Mac No. 385. This suggests to me that the F2H-2Bs were built at the factory.

The 27 (not 28) BuNos that I listed are listed in an appendix to the F2H-2 maintenance manual. That's not to say that three more were not converted after that issue of the manual.

About Me

In 1956, at age 12, I lived on NAS Sangley Point in the Philippine Islands. Always enamored with airplanes, I imprinted on the Cougars, Banshees, and Skyraiders then being deployed. Not able to be a Naval Aviator because I was nearsighted, I instead became an aeronautical engineer and general aviation pilot. Now retired, I write books and monographs on U.S. Navy aircraft.